Typewriting machine



May 28, 1935. w. 'o. MICHELSEN 2,0

TYPEWRITING MAQHI-NE Filed Sept: 5. 1934 w INVENTOR ATTORNEYS 7: Q MV 'BYfi a! 91.61

Patented May 1935- T UNITED STATES PATENT OFFICE 2,003,211 mnwnrrmc Maoimm Application September 5, 1934, Serial No. 742,787

This invention relates to new and'useful improvements in typewriting or like machines gen erally, although more particularly to the carriage escapement mechanism thereof.

Among the several objects of my invention is to provide an escapement mechanism wherein a quiet escapement action is produced during the step by step feeding movement of the carriage, and wherein a quiet action is produced between the escapementplnion and its back dog when the carriage is being moved in the opposite direction.

In the drawing:

Figure 1 is a rear elevation, partly in section, of an escapement mechanism constructed in accordance with my invention;

Figure 2 is a perspective of the wiper cam and its support;

Figure '3 is an enlarged sectional view taken on the line 3-3 of Figure 1;

Figure 4 is an enlarged sectional view taken on the line H of Figure 1; and

Figure 5 is a perspective view of a modified form of cam.

In the accompanying drawing, 5 indicates the usual rack which is attached to the carriage, and supported on the main frame of the machine below the rack is a frame A for supporting the escapement mechanism. The frame A includes two spaced horizontal arms 6, 6 and an upwardly extending vertical arm 1. Journaled in the vertical arm 1 is a shaft 8 on which is rotatable a pinion 9 having teeth It for engaging the rack 5.

Fixed tothe shaft 8 is an escapement wheel ll having teeth 12. A back dog l3 for the pinion 9 is pivoted as at ll to the escapement wheel II.

In machines as-heretofore constructed, 'a spring has been employed to yieldably retain this back dog in engagement with the teeth In of the pinion 9. This construction, resulted in a very pronounced clicking noise during the returnmovement of the carriage, due to'the spring causing the nose of the dog to ride'over each tooth of the pinion and snap against the adjacent tooth. By

means of my invention I have removed this ob jection by eliminating said clicking noise.

To this end, I have provided a spring arm B which, in this instance, is shown as being substantialy U-shaped in construction and having spaced inner and outer legs l5, l6, theinner leg I! being positioned between the outer leg 16 and the pinion 9. The free end of the inner leg I5 is fixed to the back dog l3, and the free end of the outer leg I6 is provided with a downturned portion 11 which projects through an opening l8 in the escapement wheel to thereby anchor the spring and tend to urge the back dog into engagement with the teeth III of the pinion 9. The inner leg l5 of the spring is provided with an inwardly extendin'g'V-shaped hump or projection l9 which engages the face of the pinion tooth l0 opposite the face engaged by the nose of the back dog [3; and the apex 20 of the projection is rounded. The innerleg [5 extends substantially longitudinally. of the dog and beyond the nose thereof. Thus it will be seen that the dog is provided with a forwardly extending yieldable section or stop arm which intermittently contacts the teeth of the pinion and prevents the nose of the dog from intermittently snapping against the next following teeth of the pinion.

In operation, when the carriage is'being returned, the rack 5 is moved therewith and in a direction toward the left as viewed in Figure 1. v

The escapement. wheel I I which supports the back dog I3 is held against rotation by a limber dog as will be hereinafter described The movement of the rack rotates the pinion 9 on the shaft 8, and the nose of the back dog l3 slidw over the teeth of the pinion, but is retained from snappingagainst the following teeth by the spring 25 arm B, the rounded apex of the v-shaped projection is sliding over the teeth. When the pinion ceases to rotate, the nose of .the pawl l3 and the projection I9 will be disposed on opposite sides of a tooth and in contact therewith, theinclination of the projection functioning to yieldably retain said tooth against the nose of the pawl.

The escapement wheel II is intermittently released during the step by step feeding movement of the caniage by the following noise-reducing mechanism: Pivoted on the horizontal'arms 6, i

of the escapement supporting frame A as at 2 I II is adog rocker C which carries a fixed dog 22 and a pivoted or limber dog 23 which intermittently engage the teeth [2 of the escapement wheel in the usual manner whenever the dog rocker C is rocked by the key levers. Rigidly conneeted to a bracket 24 which is fixed to the rocker C at one side of the pivoted dog 23 is an upwardly projecting vertical arm 25. A flexible U-shaped support 26 has one leg 21 rigidly connected to thelower end of the arm 25 by screws 28, and extending laterally from the upper end of the other leg 29 towardsjhe pivoted dog 23 is an arm 30 to which a wiper cam II is pivoted as at 32. This cam is. provided with a rock arm 33 to which is connected the upper end of a coil spring 34, the lower end of the spring being anchored to an ear "formed on the bracket 24.

By means of this construction the camis yieldingly held in constant wiping engagement with the pivoted dog 23, and functions to normally urge and rock said dog against a stop 36 fixed to the rocker C. The stop 36 is preferably provided with a sound deadening pad 31 for receiving the pivoted dog 23 each time the latter is released from the escapement wheel upon movement of therocker C. An adjusting screw 33, which is threadably'engaged in the upper end of the arm 25, bears against the upper end of the spring leg 23 of the cam support 26 and functions to vary the lateral position of the cam and therecam 3| and spring 34.v The rocker C is then returned to its initial position by the usual return spring, and the pivoted dog is thereby carried into the path of the next tooth of the escapement wheel, the latter being free to turn the pivoted dog 23 to its normal or starting position. Thus: instead of the dog's snapping against a fixed stop as in machines of prior constructions, the dog will be eased into its state of rest by reason of its wiping contact with the cam 3|. Any noise which might be occasioned during the return movement of the pivoted dog'23 by reason of the latters contactingthe wiper cam 3| will be absorbed by the spring leg 29 of the-cam support 26. In Figure 5 I have illustrated a modified form of wiper cam 3| which is provided with a longitudinal slot 39 forming a resultant yieldable cam finger 40 which functions to absorb and thereby reduce any noise which might be occasioned by contact between the pivoted dog 23 and the wiper cam 3| in either of the pivoted movements of the dog. 1

. I claim:

1. In a typewriter or like machine, an escapement mechanism including a rack, a pinion rotatable thereby, a pivoted back dog successively engageable with the teeth of said pinion during rotation of the latter, and yieldable means for retaining the nose of the dog out of contact with the successively following teeth of the pinion during rotation of the latter.

2. In a typewriter or like machine, an escapement mechanism, including a rack, a pinion rotatable thereby, a pivoted back dog successively engageable-with the teeth of said pinion during rotation of the latter, and yieldable means cannected to the dog and successively engageable with the teeth of the pinion during rotation of the latter for retaining the nose of the dog out of contact with the successively following 3. In a typewriter or like machine, an escapement mechanismincluding a rack, a pinion rotatable thereby, a pivoted back dog successively engageable with the teeth of said pinion during rotation of the latter, and a spring arm connected to the dog and successively engageable with the teeth of the pinion during rotation of the latter for retaining the nose of the dog out of contact with the successively following teeth of said pinion.

4. In a typewriter or like machine, an escapement mechanism including a rack, a pinion rotatable thereby, a pivoted back dog successively engageable with the teeth ofsaid pinion during rotation of the latter, and a spring arm connected to the dog andprovided with a projection for successively engaging the teeth of the pinion during rotation of the latter for retaining the nose ofthe dog out of contact with the successively following teeth of the pinion during rotation of the latter.

5. In a typewriter or like machine, an escape- -ment mechanism including a rack, a pinion rotatable thereby a pivoted back dog successively engageable with the teeth of said pinion during rotation of the latter, and a spring arm connectedtothe dog and provided with a V-shaped projection for successively engaging the teeth of the pinion during rotation of the latter for retaining the nose of thedog out of contact with the successively following teeth of the pinion during rotation of the latter.

6. In a typewriting or like machine, an escapement mechanism including a rack, a pinion rotatable thereby, a support, a back dog pivoted on the support and normally cooperating with a tooth of said pinion, and yieldable means for normally retaining the nose of the dog out of contact with the next following tooth of said pin-.

ion, said retaining means comprising a U-shaped spring arm having spaced inner and outer arms, the inner arm being connected to the dog and extending longitudinally thereof beyond the nose of the dog and contacting one tooth of the pinion, the free end of the outer arm being anchored to the support. w

7. In a typewriting or like machine, an escapement mechanism including arack, a pinion rotatable thereby, a support, a back dog pivoted.

on .the support and normally cooperating with a tooth of said pinion, andyieldable means for normally retaining the nose of thedog out of contact with the next following tooth of said pinion, said retaining means comprising a U- shaped spring arm having spaced inner and outer arms, the inner arm being connected to the dog and extending longitudinally thereof beyond the nose of the dog and having a V-shaped projection contacting one tooth-of the pinion, the free end of the outer arm being anchored to the support.

WILLIAM O. MICHELSEN. 

